Plastic material mixing device



Sept, 3, 1940.

A. L. STONE 2,213,640

PLASTIC MATERIAL MIXING DEVICE Filed April 20; 193 a Sheets-Sheet 1 .F'IE J Q lo/ary/rqm/ Y can 2; comment 8a,? Z6 55 BY @MW ATTORNEY.

A. 1... STONE PLASTIC MATERIAL MIXING DEVICE Sept. 3, 1940.

INVENTOR.

s sheets-sheet 2' Filed April 20, 1938 Sept. 3, 1940.

A. L. STONE PLASTIC MATERIAL MIXING DEVICE Filed April 20, 1938 3 Sheets-Sheet 3 INVENTOR.

ATTORNEY.

Patented Sept. 3, 1940 o PATENT OFFICE 2,213,640 PLASTIC MATERIAL MIXING DEVICE Allen L. Stone, San Francisco, Calif., assignor, by mesne, assignments, to Pneumastic 00., Inc., a

corporation of Nevada v Application April 20, 1938, Serial No. 203,017 Y 13 Claims. c1. 259-1 51) This invention relates to; device for mixing plastic materials in which the various ingredients such as water, sand and cement are conveyed by air pressure .to a tortuous mixing chamber in which a thorough mixing action is performed by virtue of the construction of the chamber and the air pressure so that a continuous mixing operation can be performed and the mixed material delivered fromthe chamber by the air pressure.

In known mixing apparatus using compressed air, all ofthe granular ingredients, such as sand and cement, are pre-mixed and must be dry for this purpose at the time they are used and are .delivered under air pressure to a nozzle where they are mixed with a jet of water immediately before delivery of the mixture in the form of a spray from the nozzle. This method is disadvantageous because to obtain thorough mixing of the cement and sand in the proper proportions the sandmust be entirely dry and the mixture must be keptdry until it is used. In

addition, for most applications it is undesirable that the mixture be delivered in the form of a spray, as it cannot be used for some kinds of work. As a result, t-heuse of this type of apparatus has been limited.

- I have discovered that an eficient mixing operation; can be performed with substantially all plastic materials of the character referred to,

by conveying the cement or similar bonding material separately in a dry state to a mixing chamber of special construction and combining it therein with the proper proportions of sand and water, which are mixed and conveyed to the chambertogether. The mixing chamber is of a portable nature so 1 that the material can be mixed at or closely adjacent to its point of application, and remote from the supply of materials.

The mixed plastic material can be obtained in substantially any desired consistency, and is discharged fromthe chamber by air pressure in the form of small balls or pellets of material, so

' that it can be used on substantially all types of 5 jobs.'- The character of use will'determine the type of discharge, and if desired, a spray can also be obtained bymaking a very thin mix and by using an appropriate nozzle.

o fore, to provide an improved method and device for mixing plastic materials adjacent the point,

of use thereof.

Another object of the invention is to provide apparatus for mixing plastic'materials, in which It is a general object of the invention, therechamber in dry form for mixing with the other ingredients.

Another object of the invention is to provide a mixing chamber for plastic materials in which the materials are conveyed thru the mixing chamber 5 by air pressure and subjected toa continuous 'mixing operation while travelling-therethrough.

Another object of the invention is to provide mixing apparatus of thecharacter referred to,

which canbe used in mixing material of a de- 10 sired consistency at a point remote from. the source of supply.

Other objects of the invention will appear from the following description of certain preferred embodiments thereof, as illustrated in the ac- 15 companying drawings, in which r I Fig. l is a schematic elevational view of the mixing apparatus. r

Fig.2 isa schematic plan view of a portion of the apparatus.

Fig. 3 is a sectional elevation of a part of the water supply apparatus. I t

Fig. 4 is a transverse sectionalview of the rotary trowel shown in Fig. 1.

Fig. 5 is'a longitudinal sectional view of the 25 mixing chamber.

Fig. 6 is a transverse sectional view of the mixing chamber taken in the plane of the line 6-6 in Fig. 5.

Fig. '7 is atransverse sectional view through 30 the mixing chambertaken in the plane of the line-'L-l in Fig.5.

' Fig. 8 is a sectional view thru the mixing chamber taken in the plane of the line 8-8 in Fig. 5.

Fig. 9'is a fragmentary enlarged sectional view 5 taken as indicated by the line 9--9 in Fig. 5.

Fig. 10 is a longitudinal sectional view of a Y modified form of mixing chamber.

Fig. 11 is a sectional'elevational view of the mixing chamber takenas indicated by the line 40 ll--ll in Fig. 10.

Fig. 12 is anend elevational view of the mixing chamberas shown in Fig. 10.

Generally, the apparatus includes sources of supply ofthe various ingredients including the water, sand, and cement, together with a source of air under pressure for conveying the material through hose lines to amixing chamber of portable nature which can be located'closely adjacent the point of applicationof the plastic material.

With the mixing chamber any suitable-form of applying device can-beused such as a hose having an open or spraytype nozzle, as desired, or a rotary trowel .of the character disclosedin my From mixer 26 the mixed plastic material may be. discharged into a flexible hose 4| (Figs. 1 and 4) from which it is used co-pending application Serial No. 176,922, filed November 27, 1937.

' Referring to Figs. 1 and 2, there is shown a water tank l4 suitably disposed with respect to a pair of sand hoppers I5 and a pair of cement hoppers l6. The respective hoppers may be conveniently mounted for cooperative relation with an air manifold H which receives air under pressure from a suitable source of compressed air l8.

The provision of the two sand and cement hoppers enables continuous operation of the mixer, as one pair of hoppers can be used while the other pair is being filled. Each of the sand hoppers |5 communicates with the air manifold |1 thru suitable valve means l9, which are also connected thru from thru flexible hose 33 which communicates with mixer26 in aJnanner later described. The hopper and air manifold connections may be of conventional construction such as those now commonly employed and are not described in detail.

Preferably, valve 23 (Fig. 3) includes shell 36 having centrally disposed spider bracket 31 mounted therein to support float valve 38, which is provided with vertically disposed rod 36 slidably engaged with the bracket to guide the movement of the valve. If pressure builds up in the line when the flow of material from the mixer is shut off, the rising level of water in shell 36 will seat float valve 38 against the upper wall of shell 36' to prevent back-flow of the water and unnecessary loss of pressure in the system.

From the above description, it is seen that dry cement and a mixture of sand and water are conveyed by air pressure to the mixer 26, whose construction and operation is described hereinafter.

as desired, either directly operations, such as groutthrough a plastic material from thehose for some ing or filling forms, or applying tool, such as of the character disclosed in said application.

Generally, the tool 42 (Fig. 4) comprises a central materialsupply tube or conduit 43 mounted centrally in split casing 44, and a material applying bell-shaped rotor 46 journalled by suitable bearing meansinot shown) on tube 43 and having respective seals 41, 48 and 48 with tube 43 and casing 44. Rotor 46 carries annular surface engaging planing blade 5| and rotary mixing and trowellingblade 52 which operate to locate thetool and control the application of the material 61118: (Fig.

' (Figs. 1 and to the surface. described is application.

Preferably, rotor 46 (Fig. 1) is driven from the source of compressed air-l6 and for this purpose is connected thereto by flexible air hose 63 4) which is connected by nozzle flt- 4) with casing 44 to direct an air jet againstblades 56 of air wheel 51 secured to rotor 46 to supply the drive therefor. Air pressure release apertures 58 are provided. in both. casing 44 and rotor 46. In operation, the plastic ma- Thus farthe tool construction rotary trowel 42, generally similar to the disclosure in said terial fed through tube 43 is received by trowel 52 and worked outwardly to the surface engaged by the planing blade 5|, the material being ap plied thereto in an even manner by the combined action of the trowel 52 and the blade 5|.

defining the passage.

with feed end plate 63 The mixer comprises generally a tortuous or zigzag chamber formed of resilientjmaterial, such as soft rubber, and having alternate enlargements and restrictions so that the material laden air stream will alternately be expanded and compressed while changing its direction of movement as it follows the zigzag passage so as to repeatedly strike and rebound from the resilient walls The respective dry and moist material discharge outlets cause such material to impinge on a resilient wall at the feed end of the passage and are thereafter carried through the chamber while being thoroughly mixed. 7 v

In the form of the invention shown in Figs. 5-9,

the mixer comprises metal cylinder or casing 6| having clamp rings 62 'threadedly engaged over.

the ends thereof in radially overlapping relation and discharge end plate 64, respectively. Compressed between end plates 63 and 64 are a plurality of chamber forming resilient segments of rubber or. the like including feed end segment 66, interchangeable interniediate segments 61 and discharge end segment 66. The segments are all formed to fit within casing 6| and to provide air pockets 1| therewith and to provide a tortuous or zigzag mixing passage between the mating faces ofthe segments.

Feed end segment 66 (Fig. 5) forms with the adjacent intermediate segment 61 an enlarged chamber 12, into which open respective conduits j 13 and 14 formed integrally with end plates 63 and having respective valve connections" and 16 with hoses 33 and 24 respectively. Conduits 13 and 14 are directed to cause the material ejected therefrom to impinge against wall 11 of chamber 12', the closing nipple-type nozzle 18 I formed integrally in segment 66 by fhaving its end wall slotted in two planes at right angles to form nipple segments 19. This construction provides for free passage of material outwardly from conduit 13, but is self-sealing when the pressure in chamber 12 exceeds that in conduit 13 go prevent any moisture fromentering the conuit.

Intermediate segments 61 (Figs; 5, 7, and 8) are interchangeable and have their facing sides recessed to form successive enlargements or chambers 8| in the straight sections of the passage and to form restrictions or necks 82 (Figs. 5-8) between the chambers 8|. As seen in Figs. 7 and 8, the chambers 8| are of substantially circular outline in one cross-sectional direction and in the other are substantially rectangular and. have a depth substantially equal to the diameter of necks 82. In this manner, the successive enlargements and restrictions of the passage are in a zigzag path of travel provided therethrough, to provide for the desired rebound and changed direction of the particles of material in travelling through the passage.

termediate segments 51 "and the length of cylin conduit "opening through self- (Figs. -5 and'9) angles to the direction of the. v

and the segment 68 is also 88 adjacent the chamber der Bl may be selected in accordance with the character of mixed material which is desired, and the required time of the mixing action.

In the form of the invention shown in Figs. 10' and 11. the construction will be described only insofar as it differs from that shown in Figs. 5-9. Casing 6| receives integrally formed passage member SI of resilient material compressed between end plates 63 and Hand secured to respective conduits l3, l4 and, 81 by respectiveclamp's 92. End plats 63 and 64 are held in place by. clamp rings 93 and a plurality ef tie rods 94 extending therebetween.

Resilient member 9! (Figs. lo and 11) is provided with alongltudinally extending material mixing passage formed in zigzag fashion with alternate enlarged chambers 8| and-necks 82 leading from the feed chamber I! into which respective feed passages 13 and 14 discharge. Passage member 9| is supported at spaced points by the casing 6| so as toprovide air pockets ll similar to the construction of Figs. 5-9.

Preferably, means is provided for adjusting the depth of the passage means to provide an adjustable restriction therein. For this purpose, leaf spring 96 (Fig. 10) is carried on the reduced end of adjusting screw 91 threadedly engaged with collar 98 secured in casing H. The ends of leaf spring 96 engage fiat walls of adjacent chambers BI and when the spring is adjusted inwardly, serve to produce an additional restriction in the respective chambers. I

The operation of the mixing device is similar for both forms and will be described with reference to the construction shown in Figs. 5-9, and with reference to the mixing of cement, sand and water.

As previously stated, dry cement is discharged through nozzle 18-;and a mixture of water and sand is discharged from conduit 14, both under pressure and carried by respective air streams, to strike against resilient wall 11 from which they rebound toward the upper wall of chamber 12 so as to produce a whirling motion therein to perform the first mixing operation, during which an expansion takes place. From chamber 12, the mixture of cement, sand and water passes through the first restriction 82, where the pressure increases and into the adjacent enlarged chamber 8| where a second expansion occurs, this operation being repeated until the mixed material is discharged through conduit 81. s

As the material moves through the zigzag passage, it rebounds back and forth between the live rubber walls, and the individual particles 'have their direction of movement changed repeatedly both by the zigzagpath. of travel and the alternate expansion and contraction afforded by'the successive enlargements and restrictions of the passage. This results in a thorough mixing action, so that the material is discharged in uniform condition from the discharge outlet.

Because the cross-sectional area of the restrictions 82 is less than the combined cross-sectional areas of the inlet passages through conduits 13 .and M, the material tends to build up in volume as it progresses through the passage, and is de-' livered from the conduit 81 in successive masses or pellets as the material fills the passage so as to be discharged by the air pressure. As pointed out, the mixed material may be delivered from dis charge conduit by means of a hose alone, or to a plastering device of the character shown.

It will be noted that the resilient construction of the passage walls will effect a continuous vibration thereof during operation to prevent cakingof the material, and to enable easy cleaning of.

the passage after use of the mixing device.

The length of the passage is determined by the character of materials being mixed, the use for which it is intended, and the desired constituency; A shorter passage is employed for thinner mixes, and also where considerable discharge force is desired, as for cement walls and filling of rock pockets, beams, columns and the like. For delivery to a mortar board or a plastering machine, where a small discharge pressure is desirable, a

.longer passage may be employed. In the form of theinvention shown in Fig. '5, the change in desired number of intermediate sections 61, with the proper length casing, while in the form shown of bothvariation and modification from the form shown, and, therefore, its scope is to be limited only bythe scope of the claims appended hereto.

I, therefore, claim as my invention: l, A plastic material mixing device comprising a resilient body having a feed chamber adjacent I one end thereof and a zigzag passage leading from said feed chamber,and having a restriction therein, and a pair of feed passages opening into said feed chamber and positioned to direct the material discharged therefrom against a resilient wall of said chamber, the combined cross-sectional area of said feed passages being greater than the cross-sectional area of said restriction.

2. A plastic material mixing device comprising a resilient body having a feed chamber adjacent one end thereofand a tortuous passage leading from said feed chamber, the resilient walls defining said passage alternately receding from and approaching each otherto provide alternate restrictions and enlargements insaid passage, and

means providing air pockets adjacent the enlargements of said passage.

3. A plastic material mixingdevice, comprising a casing, a resilient body mounted in said casing and supported thereby at spaced points to provide air pockets therebetween, and zigzag passage means extending through said body.

4. A plastic material mixing device, comprising a casing, a resilient body mounted in said casing and supported thereby at spaced points to provide air pockets therebetween, zigzag passage means extending through said body, and spring means mounted in said casing for adjustable engagement with said body to vary the cross-sectional area of said passage means.

5. A plastic material mixing device, comprising a casing, a resilient body mounted insaid casing and supported thereby at spaced points to provide air pockets therebetween, and zigzag passage means extending through said body, the

resilient walls defining said passage means alcasing and supported thereby at spaced points to provide air pockets therebetween, and tortuous passage means extending through said body and length of the passage can be effected by using the I in another transverse direction successively inhaving its discharge means of smaller size than its feed means.

'7. A plastic material mixing device, comprising a casing, a resilient body mounted in said casingand supported thereby at spaced points to provide air pockets therebetween, and tortuous passage means extending through said-body and having its discharge means of smaller size than its feed means, theresilient walls defining said passage means alternately receding from and approaching each other toprovide alternate restrictions and enlargements in said passage means.

8. A plastic mat.-rial mixing device, comprising a longitudinally extending casing, end plates adjustably connected tosaid casing, a resilient body mounted in said casing and compressed between said end plates, a feed chamber adjacent one end of said body, a tortuous passage leading through said body from said feed chamber, and means providing spaced air pockets adjacent said passage between said casing and said body.

9. A plastic material mixingdevice, comprising zigzag passage means having resilient walls, the passage formed within said walls having its dimension in one transverse direction substantially constant and having its dimension creased and decreased to provide alternaterestriction and enlargements of said passage, said restrictions being located at the bends of said zigzag passage, and means providing air pockets adjacent said enlargements.

10. A plastic material mixing device, comprising a tubular casing, a resilient body mounted in said casing having zigzag passage means ex- 'tending therethrough, said body being supported at spaced points only by said casing with the bends of said passage coinciding with said spacedpoints, the passage formed within said walls having its dimension in one transverse direction substantially constant and having its dimension in another transverse direction successively in- ,creased and decreased to provide altematerestrictions-and enlargements of said passage, said restrictions being located at the bends of said zigzag passage.

11. A plastic material mixing device, oomprising a tubular casing, a resilient body mounted in said casing having a zigzag outer contour to engage said casing at spaced points only, and

zigzag passage means extending through said body, the walls of said passage means alternate- I 1y receding from and approaching each other to provide alternate restrictions and enlargements in the passage.

12. A plastic material mixing device, comprising a frame, zigzag passage means in said frame having resilient. walls, and adjusting means mounted in said frame and engaging a wall of said passage means for controlling the crosssectional area of the passage. H

13. A plastic material mixing device, comprising a tubular casing, a resilient body mounted insaid casing having an irregular outer contour to engage said casing at spaced points only, passage means extending through said, body, and

means mounted in said casing for adjustable en -v gagement with said body to vary the cross-sectional area of the passage. v ALLEN L. STONE. 

